Conjugated linoleic acid (CLA), as a free fatty acid, has been studied extensively as a probiotic feed supplement for pigs, chickens, and other animals. See, e.g., Gavino et al., J. Nutr 130: 27-29 (2000), which is incorporated by reference. CLA is a product with health and nutritional benefits. For example, CLA is known to reduce body fat by a number of potential mechanisms, including by enhancing insulin sensitivity so that fatty acids and glucose can pass through muscle cell membranes and away from fat tissue. See, e.g., U.S. Pat. No. 6,608,222, the entire disclosure of which is incorporated by reference as if fully set forth herein. Other benefits of CLA include the stimulation of muscle growth and fat burning in animals thereby yielding leaner, more desirable (e.g., premium) animals; antioxidant properties; an ability to increase feed efficiency in animals; an ability to increase the mineral content in the bone of animals; and an ability to decrease the amount of cholesterol in the blood of animals. Id. But at the present time, CLA, in its free fatty acid form is potentially a relatively high cost approach to improve the quality indices of a meat animal's (e.g., pigs) meat. By contrast dehydrated castor oil (DCO), a commercially available product used as a low-cost and semi-fast-drying oil in the paint industry, is seen as a potentially cost effective way to introduce CLA into an animal's feed, albeit in the triglyceride form. DCO contains 25-30% conjugated linoleic acid triglyceride ester (CLA-TG) and 65-70% “normal” linoleic acid triglyceride ester (LA-TG) (i.e., not conjugated).
Though DCO has been contemplated as a feed additive for animals generally, its use for specifically improving the fat firmness and meat quality of a meat animal, particularly pigs in the finishing phase, by increasing the quality indices (e.g., iodine value) of the animal's meat has not been exploited. In addition, DCO's use to alter the ratio of saturated fatty acids to unsaturated fatty acids in meat has not been exploited.